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Qualidade microbiológica da água de cultivo e de mexilhões Perna perna (Linnaeus, 1758) comercializados em Ubatuba, SP. / Microbiology quality of the cultivation water and mussels Perna perna (Linnaeus, 1758) marketed in Ubatuba, SP.Galvão, Juliana Antunes 25 June 2004 (has links)
O consumo de moluscos bivalves pode representar sérios riscos à saúde pública, pois refletem diretamente as condições do meio ambiente. Desta forma considera-se de extrema importância o consumo de mexilhões livres de contaminação. Esta pesquisa objetivou estudar a qualidade microbiológica das águas e mexilhões de três pontos de cultivo do município de Ubatuba, SP, a saber: Engenho da Almada, Barra Seca e Costão do Cedro em um período compreendido entre novembro de 2002 e março de 2003, totalizando 5 coletas mensais. Analisou-se na água: Bacillus cereus, Clostrídios Sulfito Redutores, Aeróbios Mesófilos, Staphylococcus aureus, Coliformes totais e fecais, Enterococos e Salmonella. Nos mexilhões foram analisados os mesmos microrganismos citados para água mais o Clostridium perfringens. Os resultados encontrados tanto para as análises de água como dos mexilhões foram satisfatórios, condizentes com a legislação brasileira em vigor, salvo a coleta do mês de março, do cultivo da Barra Seca, onde a média dos valores encontrados para coliformes fecais na água (5,7x101 NMP/100mL) foi superior ao recomendado pela legislação sendo detectado também neste mesmo cultivo e mês, presença de Salmonella em 25 g nas amostras de mexilhões. Mesmo que as contagens de S. aureus e B. cereus na carne estejam de acordo com a legislação em vigor, cuidados devem ser tomados quanto ao armazenamento e a forma de consumo. Averiguou-se a intensidade de interferências sazonais na contagem microbiana na água e constatou-se que a tábua de marés e o índice de insolação diária tiveram uma correlação negativa baixa, ao contrário do índice pluviométrico que apresentou correlação positiva alta. / The consumption of bivalve mollusks can represent serious risks to the public health, because they reflect the conditions of the environment directly. This way it is considered of extreme importance the consumption of mussels without contamination. This work aims of studing the water and mussels microbiology quality from three different seafood farms in Ubatuba, SP, to know: Engenho da Almada, Barra Seca and Costão do Cedro from November 2002 to March 2003, totaling five monthly. It was analyzed in the water: Bacillus cereus, Total Clostridia, Aerobic Mesophilic, Staphylococcus aureus, total and fecal coliforms, Enterococci and Salmonella. In the mussels the same microorganisms were analyzed mentioned for water more Clostridium perfringens. The results found in the water and in the mussels were satisfactory, suitable with the Brazilian legislation, except for the sample at Barra Secas beach, in March. The average of the values found at that place for fecal coliformes in the water was higher (5,7x101 MPN/100mL) than the recommended by the legislation. Even in this collection, it was also detected Salmonella in 25 g of mussels. Even if the counts of S. aureus and B. cereus in the mussesls are in agreement with the legislation in vigor cares they should be taken with relationship to the storage and the consumption form. The intensity of seasonal interferences was discovered in the microbial count in the water, in which was verified that the board of tides and the index of daily heatstroke had a low negative correlation unlike the index pluviometric it presented high positive correlation
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Determinação da produção de resíduos sólidos provenientes do cultivo de mexilhões na região da Ilha da Cocanha - Caraguatatuba, SP / Determination of solid waste production from mussels culture in Cocanha Island - Caraguatatuba, SPFausto Silvestri 19 November 2009 (has links)
Frente ao crescimento acelerado da maricultura estão surgindo dificuldades entre as instituições governamentais para promover o desenvolvimento sustentável do setor. Com isso, aumenta cada vez mais a necessidade de se estudar a influência dos cultivos sobre os ambientes nos quais eles estão inseridos. Neste contexto, este estudo teve como objetivo determinar experimentalmente a produção de resíduos sólidos gerados pelos mexilhões cultivados na Praia da Cocanha, área com o maior adensamento de cultivos de mexilhões no litoral de São Paulo. Para isso, mensalmente entre fevereiro de 2008 e janeiro de 2009, foram desenvolvidos e executados experimentos com mexilhões de cultivo visando a quantificação dos resíduos sólidos gerados. Os resultados indicaram que a quantidade de resíduos variou significativamente conforme o tamanho dos organismos e ao longo do tempo. As variáveis oceanográficas variaram ao longo do ano sem um padrão definido e não explicaram a produção de resíduos sólidos. A produção anual estimada para a área foi de 233,8 à 718,9 (415,1 ±174,7) toneladas de resíduos sólidos conforme o adensamento dos cultivos. Em função disso, são necessários estudos específicos sobre as características hidrodinâmicas do local para que se possa avaliar a magnitude e a localização dos impactos causados pela atividade no local. / Due to the fast aquaculture\'s growth in Brazil, governmental institutions are facing difficulties to promote a sustainable development of the activity. With this, there is an increasing necessity of researches to determine the influence of mussel cultures on the environment. In this context, this study aims to experimentally determine solid waste production from mussels\' culture in Cocanha Beach, the largest mussel culture site in São Paulo State\'s coast. For this, monthly experiments with cultivated mussels where carried out from February/2008 to January/2009 to quantify the amount of solid waste produced. The results showed that the amount of solid waste produced had a significant variation with the size of the organisms and also through the year. The oceanographic parameters also varied throughout the study period but could not explain the variation in solid waste production. Annual total production was estimated in 233,8 to 718,9 (415,1 ±174,7) tons of solid waste, which varied in relation to the density of the culture. Due to these findings, further specific researches concerning local hydrodynamic characteristics are requested in order to determine the exact location and range of the area that suffers the impact derived from local aquaculture activities.
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Preparo e caracterização de um material de referência de mexilhão Perna perna (Linnaeus,1758) / Preparation and characterization of a Perna perna (Linnaeus, 1758) mussel reference materialEdson Gonçalves Moreira 28 May 2010 (has links)
A utilização de materiais de referência certificados em análise química é requisito importante em sistemas de garantia da qualidade, pois permite que métodos analíticos sejam validados e que seja obtida a rastreabilidade metrológica de resultados. Isso permite que se obtenham resultados válidos e comparáveis entre si, tanto no espaço quanto no tempo. Neste trabalho, foram realizadas todas as etapas para o preparo de um material de referência de mexilhão nacional, desde a coleta até as etapas de processamento tais como liofilização, moagem, envase e esterilização. Foram utilizados princípios internacionalmente aceitos para a avaliação da homogeneidade e da estabilidade do material, utilizando-se as técnicas analíticas de análise por ativação neutrônica instrumental e espectrometria de absorção atômica. Por meio da organização de programa colaborativo, com a participação de laboratórios nacionais e estrangeiros, foi realizada a caracterização química do material de referência de mexilhão, com determinação de elementos que ocorrem na faixa de porcentagem em massa a mg kg-1, no total de 47 elementos, além de alguns radionuclídeos naturalmente presentes no material. Com a aplicação de técnicas estatísticas adequadas, considerou-se que há possibilidade de certificação de 11 desses elementos: As, Ca, Cl, Co, K, Mg, Mn, Na, Se, Th e Zn. Esse estudo pode ser considerado passo importante no desenvolvimento metrológico nacional, pois demonstra que a produção e caracterização de materiais de referência biológicos, de mexilhão em particular, é viável no Brasil, como ferramenta de garantia da qualidade para estudos ambientais e nutricionais realizados no país. / The use of certified reference materials in chemical analysis is an important requirement in quality assurance systems, as it allows the validation of analytical methods and the realization of the metrological traceability of results. Then, it is possible to obtain valid and comparable results not only in space, but also in time. In this study, all the steps for the preparation of a national mussel reference material were attained, from the collection of the bulk material to processing steps such as freeze-drying, grinding, bottling and sterilization. Internationally accepted principles were applied for the homogeneity and stability assessment of the material, using instrumental neutron activation analysis and atomic absorption spectrometry as analytical techniques. By means of a collaborative program with participation of Brazilian and foreign laboratories, the chemical characterization of the material was performed. Element content in the mass percentage to mg kg-1 range was determined for 47 elements and some radionuclides, naturally present in the material. With the application of suitable statistical treatment to the data, it was considered that the content of 11 of those elements may be certified: As, Ca, Cl, Co, K, Mg, Mn, Na, Se, Th and Zn. This study may be considered an important step in the national metrological development, as it shows that the production and characterization of biological reference materials, mussel in particular, is feasible in Brazil, as a tool for quality assurance of environmental and nutritional studies performed in the country.
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Metal-specific high performance liquid chromatography detection approaches for the characterization of metallothionein-like proteins from freshwater musselsHigh, Kim. January 1997 (has links)
Risk assessment of environmental exposure to chronic, trace concentrations of contaminants presents an analytical challenge to interpret data in a biologically meaningful way. Biomarkers are compounds that can provide integrated information concerning the effects of contaminants on biochemical processes. The metal-binding protein, metallothionein (MT), is a biomarker of toxic heavy metals, such as cadmium (Cd), since these metals bind to MT in vivo and induce transcription of MT genes with subsequent MT protein synthesis. A high performance liquid chromatography (HPLC)-thermospray microatomization-atomic absorption spectroscopy (AAS) method was developed for detecting Cd proteins from two invertebrate models; freshwater mussels (Pyganodon grandis) from a whole lake ecosystem exposure to Cd (Experimental Lakes Area, Canada), and zebra mussels (Dreissena polymorpha) recently introduced to North America. Methods for coupling gel filtration HPLC to AAS or inductively coupled-mass spectrometry (ICP-MS) were developed to provide sensitive and selective information on metal-binding proteins in freshwater mussel extracts. Sensitive metal detection by these methods necessitated precautions to minimize HPLC column-protein exchange of metals. These interactions were relevant to the determination of low concentrations of mussel MT-like proteins (MLPs) by these metal-specific detection systems. Saturation methods employing Cd as a metallic marker for the quantification of characterized MTs were adapted for freshwater mussels exposed to low environmental Cd concentrations. Characterization of Cd-saturated mussel extracts by HPLC-ICP-MS demonstrated the presence of copper and zinc, metals physiologically bound to MT, in the principal metal-binding fraction of mussel extracts. Experimental results also indicated that mussel MLPs are not as heat-stable as mammalian MT. Zebra mussels were chosen as a bioindicator species for obtaining a standard of freshwater MT biomarker for toxi
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Effects of environmental stress on gene expression in musselsCallander, Davon Christina January 2012 (has links)
The biogeographic distribution of organisms is determined by physiological characteristics that enable a population to persist in a specific location. Global climate change effects are anticipated to increase the physiological stress experienced by organisms. Consequently, it is important to understand physiological responses to environmental stress and the mechanisms used by animals to cope with variable conditions.
I investigated the physiological response to environmental stress in two species of mussel from New Zealand, Perna canaliculus and Mytilus galloprovincialis, using quantitative PCR and ecological field experiments. A series of laboratory and field experiments were done to manipulate stress levels and the expression levels of three heat shock protein genes (hsp24, hsp70, hsp90) were measured. A transcription regulatory gene (elf2) and a cell cycle regulatory gene (tis11d) were also measured. The dynamics of stress response gene expression in response to acute stress and gene expression changes in the natural population due to varying forms of environmental stress were tested.
Between-zone translocations of different sized M. galloprovincialis and P. canaliculus were done at two sites in both east and west regions of the South Island of New Zealand. Site was found to be the most important factor in stress response. Apparent low food and high exposure stress interacted to create the particularly elevated stress response at the Timaru site. The adaptive ability of mussels transplanted between sites with varying environmental conditions was also tested. Results suggest that acclimation may be limited under stressful conditions. Furthermore, I found that P. canaliculus, the predominantly low-zone species, had a lower stress response than M. galloprovincialis, which was contradictory to predictions.
The investigations described in this thesis suggest that interactive effects of abiotic stress and food limitations are particularly challenging for animals. With the severity of climate change scenarios predicted, changes in water quality and aerial and seawater temperature suggest mussel populations are likely to be negatively affected in the future. This work also illustrates the great potential to utilise molecular techniques for analysis of physiological processes of non-model organisms in a real-world setting.
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The Hydrodynamic Effects of Long-line Mussel FarmsPlew, David Russell January 2005 (has links)
The hydrodynamic effects of long-line mussel farms are studied through a two-pronged approach. Large-scale hydrodynamic effects are investigated through the use of field measurements, primarily at a large mussel farm in Golden Bay, New Zealand (230 long-lines, covering an area of 2.45 km by 0.65 km). The research focuses on three areas: the effect of the farm on currents, mixing and stratification, and the dissipation of wave energy. Measurements are also made of the forces on long-line anchor ropes, and a limited investigation is made of phytoplankton depletion. The second approach is the use of laboratory drag measurements and Particle Tracking Velocimetry (PTV) to study the effect of mussel dropper (vertical lengths of mussel-encrusted crop rope) roughness and spacing on flow at small scales. These experiments provide data on very rough cylinders, and on cylinder arrays. The field measurements show that the local effects of mussel farms on currents are significant, but that magnitudes of the effects depend on dropper density, mussel sizes, orientation of the long-lines to the flow, and other parameters that are necessary to characterise the complex interactions between a farm and the flow. The drag on the submerged structures reduces water velocities within the Golden Bay farm by between 47% and 67%. Mussel farms present a porous obstacle to the flow, and flow that does not pass through the farm must be directed around or beneath it. The field measurements indicate that at the study site, most of the flow is diverted around the farm despite its large horizontal dimensions. The droppers at the study site extend over most of the water column (average dropper length ~ 8 m, average water depth ~ 11 m), providing a restriction to the flow beneath the farm. The strength of the density stratification may also favour a horizontal diversion. The flow around the farm is essentially two-dimensional. This suggests that two-dimensional numerical models should be sufficient to obtain reasonable predictions of the velocity drop within, and the diversion around, mussel farms. A simple two-dimensional pipe-network model gives reasonable estimates of the velocity within the farm, demonstrating that the drag of the farm may be adequately parameterised through local increases of bed friction. A wake in the form of reduced velocities extends downstream of the farm, and a mixing layer analogy suggests that this wake spreads slowly. The downstream extent of the wake cannot be determined, although it is likely to be limited by the tidal excursion. The degree of vertical mixing caused by the flow through a mussel farm cannot be quantified, although there are clear interactions between the stratification and the farm. Two mixing mechanisms are considered. A shear layer is generated beneath the farm due to the difference in velocities between the retarded flow within the farm and the flow beneath. Shear layers beneath mussel farms are likely to be weak unless the ambient currents are strong. It will be necessary for stratification to be weak or non-existent for this mechanism to generate significant mixing. The second mechanism is smaller-scale turbulence generated by the mussel droppers. Although the efficiency of this form of mixing is likely to be low, the large number of mussel droppers suggests that there will be some enhancement of vertical mixing. Frequency-dependent wave attenuation is recorded, and is predicted with some success by an analytical model. Both the model and the field data show that wave dissipation increases as the wave period decreases. Wave energy dissipation at the study site averages approximately 10%, although the measurements are made during a period of low wave heights (Hs < 0.25 m). Measurements of long-line anchor rope tension at two study sites indicate that the loadings are induced by the tide, currents, and waves. Dynamic wave loadings may be significant, and higher wave forces are measured at the offshore end of a long-line. The issue of seston or phytoplankton depletion is considered briefly through the examination of fluorescence, turbidity, and acoustic backscatter data. Although the results are consistent with a reduction of seston within the farm, differences between the inside and outside of the farm are not statistically significant. Mussel droppers resemble extremely rough circular cylinders, with the mussel shells forming the surface roughness elements. Drag measurements and PTV flow visualisation are used to investigate the importance of the large surface roughness, and the influence of dropper spacing and long-line orientation on flow. Drag measurements conducted with smooth and rough cylinders show that high surface roughness (ks/D ~ 0.092) has little effect on the drag coefficient of single cylinders in the range 4,000 < Re < 13,000, yet increases the drag coefficient of a row of cylinders normal to the flow. High surface roughness on single cylinders has the effect of shortening the near-wake region, increasing the peak turbulent kinetic energy (TKE) behind the cylinder, and decreasing the Strouhal number (St = 0.21, 0.19, 0.17 for ks/D = 0, 0.048, and 0.094 respectively). Arrays of rough cylinders (ks/D = 0.094) demonstrate similar flow characteristics to those of smooth cylinders. At cylinder spacings of S/D < 2.2, the surface roughness acts to favour the formation of a particular metastable wake pattern, whereas different metastable wake patterns are formed each run behind the smooth cylinders. The experiments show that the drag on single row arrays of cylinders are related to the cylinder spacing (increasing drag with decreasing spacing), and the drag also varies with the sine of the angle to the flow, except where the array is at low angles to the flow. The PTV measurements provide new data regarding the two-dimensional distributions of velocity, TKE, and turbulence statistics behind the cylinder arrays.
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Trends in the nearshore zooplankton community in the Indiana waters of Lake Michigan, 1990-1996Ng, Patti A. January 1997 (has links)
Zooplankton samples collected May through August, 1990 to 1996 at site M, 15 m depth in the Indiana waters of Lake Michigan were examined for microcrustaceans, rotifers, and zebra mussel (Dreissena polymorpha) veligers. Abundance numbers per m3 were combined with Coffman's (1995) data to quantify recent trends in the zooplankton.Rotifers dominated the community, with Polyarthra vulgaris, Colurella, Keratella crassa, and K. cochlearis the most prevalent species. Copepods, primarily nauplii and copepodid forms, were the next most abundant taxa. Except for 1994 and 1995, Cladocera abundance was higher than zebra mussel veliger abundance. The cladoceran assemblage was dominated by Bosmina Iongirostris, with very few Daphnia noted. A precipitous decrease in zebra mussels veligers from 1994 to 1996 warrants further investigation to determine the nature and the extent of the population decline.Regression analysis of zebra mussel veliger abundance against abiotic and biotic factors demonstrated veligers varied directly with rotifer abundance and water column temperature and indirectly with cladoceran and yellow perch (Perca flavescens) abundance. A similar regression model of rotifer abundance revealed direct correlation with calanoid, cladoceran, zebra mussel veliger, and yellow perch abundance. / Department of Biology
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Quantificação de metais potencialmente tóxicos em mexilhão dourado (Limnoperna fortunei) por espectrometria de absorção atômica com fonte contínua e alta resolução empregando amostragem direta de sólidos / Quantification of potentially toxic metals in golden mussel (Limnoperna fortunei) with high resolution continnun source atomic absorption spectrometry using direct solid sampleSilva, Ana Caroline Soncin [UNESP] 29 March 2016 (has links)
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Previous issue date: 2016-03-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O mexilhão dourado (Limnoperna fortunei) tem provocado transtornos ambientais e econômicos nas localidades onde foi introduzido. Dessa forma, o uso do seu resíduo moído como reparador da defasagem de nutrientes e de acidez em solos agrícolas pode vir a ser uma boa aplicação para esse molusco bioinvasor. Entretanto, apesar dessa ação reparadora, é necessária uma averiguação prévia da ausência de elementos potencialmente tóxicos no resíduo. Neste contexto, o presente trabalho foi realizado com o intuito de quantificar, em amostras do Limnoperna fortunei, os elementos chumbo, cádmio, alumínio, ferro e manganês, os quais dependo de suas quantidades podem ser tóxicos aos vegetais e aos demais seres vivos ao longo da cadeia alimentar. Para quantificação desses analitos foi utilizada a Espectrometria de absorção atômica com fonte contínua e de alta resolução. Foram desenvolvidos e otimizados programas de aquecimento para a determinação dos elementos traço chumbo e cádmio, empregando amostragem direta de sólidos e atomização com forno de grafite. A determinação direta de chumbo só foi possível com a utilização da calibração com o material de referência certificado para tecido de mexilhão (Mussel Tissue – 2976), empregando 5 µL da mistura 0,1% (m/v) Pd (NO3)2 + 0,05% (m/v) Mg (NO3)2 em presença de 0,05% (m/v) de Triton X-100 como modificador químico. As temperaturas de pirólise e atomização foram 1000°C e 2200°C, respectivamente. O estudo de massa permitiu a utilização de massas de amostras dentro da faixa de 0,150 a 0,850 mg. Para o cádmio só foi realizada calibração com solução padrão 12,5 µg/L, também com o uso de 5 µL do modificador químico Pd+Mg. Assim, foram alcançadas temperaturas de pirólise de 900 °C e de 1600 °C para a atomização. O estudo de massa precisou ser desenvolvido com uma das amostras coletadas e demonstrou que puderam ser usadas, para as quantificações, massas próximas a 0,250 mg. Os limites de detecção e quantificação foram, nessa ordem, 0,009 mg/kg e 0,03 mg/kg para o chumbo, e 0,0004 e 0,001 mg/kg para o cádmio. No caso dos elementos alumínio, ferro e manganês, as quantificações foram realizadas utilizando a atomização com chama. Os limites de detecção e quantificação foram, respectivamente, 0,15 mg/kg e 0,50 mg/kg para o alumínio, 0,050 mg/kg e 0,15 mg/kg para o ferro, e 0,00067 mg/kg e 0,0023 mg/kg para o manganês. Os resultados para todos os elementos quantificados nesse estudo apresentaram concordância de 95% com o test-t (Student) não pareado, o que valida e viabiliza os métodos desenvolvidos para as quantificações de chumbo e cádmio, bem como comprova a exatidão dos demais resultados obtidos. Portanto, as técnicas analíticas selecionadas foram eficientes para as quantificações dos elementos desejados no resíduo moído desse mexilhão dourado. / The golden mussel (Limnoperna fortunei) has caused environmental and economic disruption in the locations where it was introduced. Thus, the use of their ground waste as repairer of the gap of nutrients and acidity in soils may prove to be a good application for this mollusk bio invader. However, despite of this remedial action, a prior test of the absence of potentially toxic elements in the residue is required. In this context, the present study was performed in order to quantify, in samples of the Limnoperna fortunei, the elements lead, cadmium, aluminum, iron and manganese, which depending on their quantities they can be toxic to plants and other living beings throughout the food chain. To quantify these analytes was used high-resolution continuum source atomic absorption spectrometry. Heating programs were developed and optimized for the determination of lead and cadmium trace elements, using direct solid and graphite furnace atomization. The direct determination of lead was only possible with the use of calibration with certified reference material for mussel tissue (Mussel Tissue - 2976), using 5 uL of the mixture 0.1% (m/v) Pd (NO3)2 + 0.05% (w/v) Mg (NO3)2 in the presence of 0.05% (w/v) Triton X-100 as a chemical modifier. The temperatures of pyrolysis and atomization were 1000 ° C and 2200 ° C respectively. The mass study allowed the use of samples of mass within the range of 0.150 to 0.850 mg. For cadmium it was only performed calibration with standard 12.5 g/L solution, also using 5 uL chemical modifier Pd + Mg. Thus, pyrolysis temperatures were reached 900 ° C and 1600 ° C for atomization. The mass study needed to be developed with one of the samples collected and it showed that they could be used for the measurements, masses close to 0,250 mg. The limits of detection and quantification were, in this order, 0.009 mg/kg and 0.03 mg/kg to lead, and 0.0004 and 0.001 mg/kg to cadmium. In case of the elements aluminum, iron and manganese, the measurements were carried out using atomization with a flame. The limits of detection and quantification were, respectively, 0.15 mg/kg and 0.50 mg/kg to aluminum, 0.050 mg/kg and 0.15 mg/kg for iron, and 0.00067 mg/kg and 0.0023 mg/kg to manganese. The results for all quantified elements of this study showed agreement of 95% with the t-test (Student) unpaired, which validates and enables the methods developed for lead and cadmium quantifications and proves the accuracy of the other results. Therefore, the selected analytical techniques were efficient to the quantifications of the desired elements in the ground waste this golden mussel.
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Intertidal patterns and processes tracking the effects of coastline topography and settlement choice across life stages of the mussels perna perna and mytilus galloprovincialisVon Der Meden, Charles Eric Otto January 2010 (has links)
Within landscapes, spatial heterogeneity is common and specific landscape features can influence propagule dispersal by wind or water, affecting population connectivity and dynamics. Coastline topographic features, such as bays and headlands, have a variety of biophysical effects on nearshore oceanography, larval transport, retention and supply, and the processes of larval settlement and recruitment. Although this has been demonstrated in several parts of the world, engendering a perception of a general ‘bay effect’, few studies have investigated this generality in a single experiment or region, by replicating at the level of ‘bay’. The Agulhas biogeographic region of the south coast of South Africa is a useful system within which to test for such generality. Using the intertidal mussels Mytilus galloprovincialis and Perna perna as model organisms, patterns of adult distribution were surveyed across four large ‘halfheart’ bays and intervening stretches of open coast, providing replication at the level of ‘bay’ and duplication of ecologically similar species. In support of a general, pervasive influence of bays on intertidal populations, mussel cover was found to be greater in bays than on the open coast for both species, although the effect was strongest for M. galloprovincialis. To explain this adult distribution, settlement, post-settlement mortality and recruitment were examined over 12mo at the same sites, with the prediction that rates of each would favour larger bay populations. Contrary to this, an interaction between month and bay-status was found, with greater settlement and recruitment on the open coast than in bays reflecting extreme settlement and recruitment events at 3 westerly open coast sites during summer. Re-analysis excluding these outliers, revealed the expected effect, of greater settlement and recruitment in bays. While this indicates the broad generality of the bay effect, it highlights exceptions and the need for replication in time and space when examining landscape effects. Measuring post-settlement mortality required testing small-scale settlement behaviour on established and newly deployed settler collectors. It was found that all settlers preferred collectors with biofilm, but that primary settlers avoided conspecific settlers, while secondary settlers were attracted to them. With discrepancies in settler attraction to new and established collectors accounted for, initial (over 2d) and longer-term (over 7d) post-settlement mortality rates were found to be substantial (ca 60 %) for both species. No topographic effect on p-s mortality was evident. Finally, recruit-settler, adult-recruit and interspecies correlations were examined at regional and local scales. Synergistic (or neutral) effects maintained the initial settlement pattern in recruit and adult populations regionally, but not at local scales; striking interspecies correlations suggested the influence of common regional transport processes. Ultimately, the results emphasize the importance of the direction of effects in different life stages and at different spatial scales, and the possibility that antagonistic effects may mask even strong patterns.
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Fatores ambientais que afetam a distribuição e estrutura populacional de bivalves límnicos em lagoas adjacentes ao Rio CuiabáMichiura, Anderson Wakinaguni 27 February 2015 (has links)
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Previous issue date: 2015-02-27 / CAPES / Os bivalves de água doce são um grupo com alto risco de extinção devido às mudanças climáticas, expansão urbana, construção de reservatórios hidrelétricos, crescimento populacional, eutrofização, degradação dos habitats, poluição pontual e difusa dos ecossistemas aquáticos. O objetivo deste trabalho foi identificar quais fatores físicos e químicos da água e sedimento que determinam a estrutura da comunidade de bivalves em 18 lagoas adjacentes ao rio Cuiabá, nos ambientes urbanos e não urbanos. A amostragem dos bivalves foi realizada pelo tateio no fundo das lagoas e por coleta de sedimentos ao longo do transecto com auxílio de uma peneira. Variáveis físicas e químicas da água e % de matéria orgânica do sedimento foram mensuradas e usadas como preditoras da abundância e estrutura da comunidade de bivalves pela ordenação da análise de componentes principais, regressão multivariada e análise de redundância (RDA). A RDA demonstrou uma relação das concentrações de nitrato e % de matéria orgânica com a estrutura da comunidade de bivalves. As espécies encontradas foram A. trapesialis (50,66%), Pisidium sp. (26,98%), C. fluminea (7,48%), C. inflata (6,82%) e A. elongatus (6,16%). As populações de A. trapesialis e A. elongatus estiveram relacionadas positiva e significativa com o nitrato. O aumento da % de matéria orgânica no sedimento esteve relacionado com menor abundância de A. elongatus, entretanto pouca relação com a classe de comprimento das valves. A espécie A. trapesialis teve efeito positivo e significativo com a variável oxigênio dissolvido em relação à classe de comprimento das valves. Os fatores ambientais que refletem os nutrientes podem influenciar na distribuição da comunidade de bivalves de água doce, no entanto, não determinam a estrutura da comunidade em lagoas urbanas e não urbanas. / Freshwater mussels are a group at high risk of extinction due to climate change, urban expansion, construction of hydroelectric reservoirs, population growth, eutrophication, habitat degradation, pollution and diffuse spot of aquatic ecosystems. This works was to identify which physical and chemical factors of the water and sediment that determine the structure of mussels community in 18 of ponds the Cuiaba river, in urban and non-urban environments. Sampling of mussels was conducted by groping the bottom of ponds and collecting sediment along transect with the aid of a sieve. The physical and chemical water variables and % organic matter in the sediment were measured and used as predictors of abundance and structure of the mussel community by ordering the principal component analysis, multivariate regression and redundancy analysis (RDA). The RDA showed a ratio of nitrate concentrations and % organic matter having the structure of mussels community. The species were A. trapesialis (50,66%), Pisidium sp. (26.98%) C. fluminea (7,48%), C. inflata (6,82%) and A. elongatus (6,16%). Populations of A. trapesialis and A. elongatus were positively and significantly related to nitrate. Increased % of organic matter in the sediment was associated with a lower abundance of A. elongatus, however little to do with the length class of valves. The species A. trapesialis had a positive and significant effect on the variable dissolved oxygen relative to the valves length class. Environmental factors that reflect the nutrients may influence the distribution of freshwater mussels community, however, not determine the community structure in urban and non-urban environments.
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